Lightroom noise reduction explained

Since i just posted about sharpening, i’ll write one more about noise reduction. Sharpening and noise reduction go hand in hand and in Lightroom, they’re located on the same tab – the one named “Detail”.

As a rule of thumb, you want to do your noise reduction before you do your sharpening, because if you begin by sharpening, you’ll sharpen your noise and it will look worse.

Noise reduction comes with six sliders, but usually you will only be using two of them: color and luminosity. Go into the develop module of Lightroom and you’ll find the detail tab on the right. Notice a couple of very helpful things. First, the exclamation mark (red arrow) that tells you your image is not zoomed in enough to work with noise reduction and sharpening. Click on it and you get a 100% preview. Second, if you click on the black arrow (yellow arrow), you will get a small detail window. Now the exclamation mark has been replaced by a symbol that you can click on to select which part of the image you want to see in your small details window.

Detail tab

So what is noise and why do we get it? Noise is a graininess and pixel-level discoloration of your images that you get when you push your camera hard in situations with less light. If you raise your ISO to be able to get lower shutter speeds in low light situations, you will get noise. Some camera sensors do this better than others, of course. I’m fortunate enough to have lots of noisy images, because i shoot my daughter’s handball team in badly lit places. I’ll set my ISO to 3200, which is very high, to be able to take pictures at reasonable shutter speeds. Let’s look at what Lightroom can do for a picture like this one:

Noise reduction before full size

Let’s begin with both luminance and color noise sliders set to zero. The color slider defaults to 25, but i pulled it down to zero for our starting point. If we zoom in closely on the nearest girl’s face area, we see very clearly that there’s color noise, which is the pixels with different colors. There’s also a lot of luminance noise, which is the pixels that are in the right color range, but too dark or too bright, which makes the stand out from their surrounding area.

Starting point

Our first step is to pull the color noise slider up to around 33.

33 color noise reduction

Notice what a great job Lightroom has done. The discolored pixels are gone. Now we pull the luminosity slider up to around 40.

Luminosity 40 color 33

After this step, much of the grain has been reduced. Since we started with a terribly noisy image, it will never get perfect, but we’ve come a long way. This far is mostly where i’ll go, because i’ve found that working with the other sliders will usually only make things worse. Adding contrast pulls noise back into the image and pulling the detail sliders up or down pulls back noise too. If you go any higher with the color slider, the image will start to fall apart. Here’s our image with the color slider at 100:100 color noise reduction

If we go higher on the luminosity slider, our subject will start looking like a porcelain doll because the grain has been evened out to something that no longer looks natural.

Noise reduction luminosity 100

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Lightroom sharpening explained

First of all, let’s make one thing clear. Sharpening will not save your bad blurry images. That’s not what this functions is about. It’s about improving an already good and sharp image. How much sharpening you should do is of course a matter of taste. It also depends on how you intend to use your image. However, if you’re processing your RAW images without doing any sharpening, you’re really losing a lot of quality. Your images are intentionally slightly blurred when the image is mixed from the information captured by the red, green and blue shades from your camera’s sensor (a process called demosaicing).

It’s generally recommended that you do your sharpening late in your development process, after any exposure adjustments and clarity. Sharpening goes hand in hand with noise reduction, so those two are usually done together.

Besides being a lot easier, sharpening in Lightroom does a much better job than Photoshop. It only sharpens the luminosity (black and white) c0mponents of the file, which is a good thing, because there’s no risk of color artifacts being created by the sharpening.

The sharpening controls are located on the Details tab in the develop module. There are four sliders.

Lightroom Detail

Amount controls the intensity of the sharpening.

Radius controls the area which is sharpened. If your image is already sharp, it’s recommended that you set this value to 1 pixel or less. If there’s any blur in your image, you might get a better result with an increased radius.

Detail controls the amount of contrast that is added within the radius you have selected. Generally, increasing the detail works best for subjects such as landscapes. For portraits, adding detail doesn’t look good. This slider has a default value of 25, which actually is a bit high if you’re for example working with portraits. Consider decreasing it a little.

Masking controls where all the three settings above are being applied in your image. By holding down the alt key (Option on a Mac), while using this slider, you will se what areas will be left unaffected by the sharpening. This is everything that is black in the preview. This is a good way to avoid sharpening noise in large areas in the image and thereby adding artifacts.

Zoom in closely on your image, so you can really see how every slider affect the results of your sharpening.

A good way to see what the sliders are doing, begin by pulling the amount slider all the way up to 150. This allows you to see much better what the other three sliders are doing. Once you’re satisfied with your radius, detail and masking, reduce the amount down to a level that’s not  as exaggerated. At high levels, you’ll notice that the sharpening generates noise, especially in darker areas. Pull back the amount until the noise is gone or at least almost gone, and use noise reduction to take care of what is left. I’ll write a post about noise reduction within the next couple of days, so check in for that if you’re interested.

For all four of these sliders, there’s a preview function that allows you to see what’s happening. I think it’s especially useful for the masking slider, as i described above. Hold down the Alt key (option on a Mac) to see the preview.

To finish up your work, consider checking the “Remove Chromatic Aberration” checkbox, which is located on the Lens Corrections tab in the develop module. It will remove any edge artifacts, usually magenta colored, in your image.

Chromatic aberration

Once you’re starting to feel finished, bring up the before/after view, using the menu View->Before / After->Split Screen (Shift + y), to see how your sharpening adjustments have improved your image.

Lightroom comes with two presets for sharpening. If you haven’t (like me) deleted them, they can be found under Presets->Lightroom general presets, there are two sharpening presets: “Sharpen Faces” and “Sharpen scenic”.These presets will give you a general idea of how to sharpen portraits and landscapes.

If you want a very general rule of thumb, pulling the sharpening amount to around 70 and the noise reduction to 30-40, while keeping all other sliders on the Detail tab as they were, you’ll get a pretty good sharpening/noise reduction combination.

The technical explanation

If you want to see on a very detailed level what sharpening does. Here’s an interesting experiment. Go into Photoshop and create a new image from scratch. Fill one half of it with dark gray and the other half with light gray. You’ll end up ith something like this:

grayscale

Now import this image into Lightroom. Bring it into the develop module and zoom in on the border between dark and light gray. Now pull up the sharpening amount and notice what happens. You may need to bring it back into Photoshop to see the details. It darkens the pixels in the outer edge of the darker part and lightens the outer pixels in the light part, creating an illusion of sharpness. Also notice how pulling the radius and detail sliders up and down change the effect. You’ll also notice some banding right next to the bordering pixels.

This is a close-up that shows on pixel level what happens. The amount slider has been pulled all the way up to 150 and the radius is 1.0. Above the black line is before and below is after the sharpening.

sharpening

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Get on your belly for better images of your pet

You see a lot of pictures of people’s dogs and cats these days. Very often, they’re taken from a standing up position, with the pet sitting below looking up. This might be how you most often see you animal, but it’s pretty boring.

Boring cat picture

It’ very easy to get a better picture. Let me give you a few tips.

First of all, get down there with your little friend. You’ll get much better images if you’re down at the same level. Also, getting closer is almost always a good tip for any type of photography.

Black and white cat sleeping

Don’t take just one or two pictures, take a lot. Try different environments, situations and angles. Play around and take a hundred pictures and weed out the bad ones afterwards. I had this little guy running around for half an hour in the backyard and came back with hundreds of images. This is the one i picked out, which caught his happy and playful personality perfectly.

Happy puppy running in the grass

Set up fun situations

Take a look at these pictures of two bengal cats. By letting them play in a cardboard box, i was able to catch a few funny and cute situations.

Bengalk cats playing in a box

Make sure you focus on the eyes

Like in any portrait photography, it’s very important that the eyes are in focus. If your camera allows selecting specific focus points, consider using this function to get the focus right where it needs to be.

Kitten eyes

Black pets take some extra work

A black dog or cat can be tricky when it comes to lighting. You may need to adjust the exposure settings on your camera if your pet fills up the frame, because the camera tries to compensate for the darkness. Also, it may take some post processing to bring out the structure in black fur. Get your pictures into Lightroom and experiment with the exposure, highlight, shadow, blacks, whites and clarity sliders. Also, make sure the picture is sharpened in post processing.

Black furry Riesenschnauser

Get the details

Move in close and get a few pictures of those little details, like the paws or the nose.

Little cat details

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